These studies are being conducted to evaluate potential human exposure for manufacturing compounds that have high production, increasing use and/or structural similarity to other known toxicants. There is limited environmental and occupational exposure data available in the scientific literature to assess the acute exposure/ response relationship, and potential chronic long-term adverse effects of EGEHE exposure. Validation of passive (diffusive) and active (pumped) sampling methods is ongoing. Due to problems encountered in the Gas Chromatography Mass Spectrometry method,an alternative Liquid Chromatography Mass spectrometry method is being explored. Additional sampling has been delayed pending an assessment of the utility of this method.